A circulating fluid is often used to control the temperature of a processing chamber or walls of a device, such as an constant-temperature tank, semiconductor manufacturing device (etching device or CVD device for example), or plastic plate thermocompression molder. In Japanese Patent Laid-open No. 7-280470 and Japanese Patent Laid-open No. 7-308592 are disclosed devices suitable for controlling the temperature of a circulating fluid.
The device disclosed in Japanese Patent Laid-open No. 7-280470 has an electric heater inserted into a pipe in which is flowing a fluid; covering the outside surface of this pipe is an even larger pipe, and cooling water is made to flow between the outside pipe and inside pipe. The electric heater and the cooling water are used to control the temperature of the fluid.
The device disclosed in Japanese Patent Laid-open No. 7-308592 has a radiator joined via a thermoelectric conversion element to a heat transfer block, on the inside of which is made to flow a fluid. The fluid flowing in the block is cooled or heated by the thermoelectric conversion element. The heat absorbed by the thermoelectric conversion element from the fluid is discharged to the atmosphere by a radiator.
The above-mentioned conventional fluid temperature control devices have the following disadvantages, in particular as relates to cooling performance.
The device in Japanese Patent Laid-open No. 7-280470 cannot cool the fluid below the temperature of the cooling liquid, which means it has a narrow cooling temperature range. Further, in general, it is difficult to make fine adjustments to the cooling liquid temperature or flow volume, so if the fluid temperature is not finely adjusted by also using a heater during cooling, then the fluid cannot be cooled to the target temperature with good accuracy.
The device of Japanese Patent Laid-open No. 7-308592 discharges heat to the atmosphere from a thermoelectric conversion element during cooling, but the low heat capacity of the atmosphere causes the cooling capacity to be low, which means it is difficult to process a large quantity of fluid in a short time. Further, because the thermoelectric conversion element is used for both heating and cooling, the controllable temperature range is not very wide and the life of the thermoelectric conversion element is shortened.